Inorganic salts of sulfurous acid have heretofore been discovered by one of us (Jose Antonio Arias Alvarez) to have anticoagulant and antithrombotic properties; see U.S. Ser. No. 227,382, filed Jan. 22, 1981 and Ser. No. 271,850 filed June 16, 1981, and now abandoned in favor or copending application Ser. No. 337,176 filed Jan. 5, 1982.
Anticoagulants and antithrombotics are a group of compounds with diversified pharmacologic actions used in a variety of chemical thrombotic disorders. Thrombotic disorders are generally divided into venous thromboses and arterial occlusive disorders. Venous thrombosis of the lower extremities is important because it can cause pulmonary embolism which may be fatal. Heparin and warfarin are commonly used in clinical medicine for prevention and treatment of deep venous thrombosis and pulmonary emboli. Their pharmacological actions are in the inhibition of blood coagulation activity (i.e., heparin) or of synthesis of coagulation factors (i.e., warfarin). Platelets play an important part in arterial thrombosis. Drugs that inhibit platelet aggregation are generally regarded as being potentially useful for prophylactic therapy of arterial thrombotic disorders, including, for example, stroke, myocardial infarction, and peripheral vascular disease. Despite the availability of many agents which possess anti-platelet aggregating properties, only a few are currently under clinical trails (for example, aspirin, dipyridamole, sulfinpyrazone). None of these exhibit unequivocal efficacy. Compounds with more specific pharmacological action are urgently sought in order to provide better medical care for patients with these serious disorders.
An anti-platelet aggregatory agent is a substance which inhibits platelet aggregation.
An antithrombotic agent is a substance which inhibits formation or development of a thrombus (or thrombosis). For present patent purposes, it will be understood that the term "thrombus" or equivalent includes the subject matter of the term "embolus" unless specifically indicated. In general, an antithrombotic agent may display, in the presence of mammalian blood or appropriately prepared plasma, anticoagulant activity and/or anti-platelet aggregatory activity.